Piston construction



March '13, 1951 N. J. BUREN PISTON CONSTRUCTION Filed 001;.- 27, 1948 :El El Patented Mar. 13, 1951 UNITED STATES PATENT OFFICE rIsTON CONSTRUCTION Newton .L Buren, Tacoma, Wash.

Application october 27, 194s, seria1N0.56,'151

10 Claims.

forces because it is not stiff enough to resist them. This results in noisy action, loss of power through wearing the faces of the piston rings slightly rounded, resulting further in oil pumping. A iiexible piston hinges opposite the siot where there is no means provided to stiften that portion of the skirt.

Definite means for overcoming the disadvantages above set iorth is found by providing eccentric ribbing of eccentric contour in cross section to offset the iiexibility of the usual split skirt piston. The eccentric ribbing replaces a large amount of the rigidity lost when splitting the piston skirt. As shown in said prior patent. the eccentric ribs of the piston are disposed well away from the open end Or mouth of the piston. In so disposing eccentric ribs a considerable extent of the slotted skirt is left with but little support from the eccentric rib.

The present improvement overcomes the defects in prior devices including the patented structure referred to by providing an internal centering rib concentric with the piston contour at the extreme end of the piston skirt so that the piston may be conveniently and accurately oentered, while the eccentric rib instead of being well away or spaced from the concentric rib and open end or mouth of the piston, is located immediately adiacent thereto and as close to the end of the skirt as possible and merging therewith as one, not only to more electively eliminate chatter or vibration but to permit proper'centering and enhance same.

In view of the foregoing it is one important object of the invention to provide a piston coni struction in which an eccentric rib is so posi- 'tioned as to most electively resist chatterv or vibration due to unsupported parts of the slotted f portion of the skirt.

Pistons of this character are finished externally in most cases by turning on a lathe, a mandrel being inserted inthe open mouth ofthe piston'and a dead center carried by the tail stockof the lathe being engaged in a suitable center hole formed in the closed end of the piston. To enable the mandrel to have a proper nt in the piston the latter is yprovided at its mouth with an internal rib extending around the piston concentric with the axis thereof.

Another important object of the invention` is to provide an improved piston construction wherein an internal concentric rib at the mouth is merged with an eccentric so that there exists the shortest possible moment arm between the eccentric rib and the annular edge of the piston mouth.

A further important object of the invention is 'to provide a piston having an internal concentric rib at its mouth and having an eccentric rib merging with the concentric rib and extending toward the closed head of the piston with gradually decreasing eccentricity.

' With the above and other Objects in view, as

will be presently apparent, the invention consists` in certain novel arrangements and combinations of constructional details hereinafter fully described, illustrated in the accompanying drawings and particularly claimed.

In the accompanying drawings like characters of reference indicate like parts in the several views and:

Figure 1 is a sectional view extending diametrically through one form of piston constructed in accordance with this invention.

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a diametric fragmentary view through the mouth portion of a piston showing a modication of the eccentric rib arrangement.

Figure 4 is a similar view showing a second modification of the eccentric rib.

In the forms of the invention as illustrated in the drawings there is disclosed a piston It of the type usual in internal combustion engines being in the general form of a hollow cylinder having one end I I closed and its other end open to form a mouth |21 While the piston Will vary in posivtion in accordance with the type of engine in Ausual piston rings and at one side the wall of the piston is provided with a transversely extending or elongated radial slot I5 leading inward from the Iowermost groove I4. The upper part of the piston is provided withl a -pair of oppositely disposed internal bosses I6 provided with axially alined openings i1 for the reception of a wrist pin. The bosses are reinforced by ribs I8 extending to the head Il and by ribs I9 and 2i! extending to the side wall of the piston. It is to be noted that the arrangement of the bosses and the ribs extending therefrom may be varied at will without departing from the essential principles of this invention.

At the mouth I2 the piston is provided with an internal rib 2i extending around the inside of the piston wall and concentric to the axis of the piston and thus concentric to the outer side face of the piston when the latter is nished. The lower hollow part of the piston forms a vskirt 22. This skirt is provided with a radial slot 23v through its wall parallel to the piston axis and extending upwardly from the bottom of the piston to the slot l5, this slot 23 also extending through the ribs i9 and 2l.

As shown in Figures l and 2, the piston is provided with an eccentric rib 24, the center of eccentricity of this rib being displaced from the axis of the piston on a line extending diametrically rom the slot 23 through the axis of the piston and at a lesser distance from the slot than said axis. With the eccentricity of the rib 24 the thickest part of said rib lies diametrically opposite the slot 23. The rib 24 has its thickest part of less radial extent than the radial extent of the rib 2i so that no part of the rib 24 extends inwardly of the rib 2l. Moreover the lower face extent of the rib 24 is coincident with the upper face extent of the rib 2i so that the two ribs merge.

In the form shown in Figure 3, the eccentric rib 25 is generally arranged like the rib 24 but, instead of being substantially uniform in width or depth and its upper surface merging in a substantially abrupt manner with the inner surface of the skirt 22 it merges gradually with said inner surface as along the line 26 such as on a concaved arc rising from the narrowest part of the rib 25 at slot 23 to a point diametrically opposite the slot 23.

In Figure e the rib 21 extends well up along the skirt 22 much wider or deeper than rib 24 but may also be of substantially uniform width or depth and in this form, as well as that of Figure 3, the widest part of the eccentric rib is diametrically opposite the slot 23 and does not extend into the open circle of the rib 2|.

It will now be plain that the eccentric rib of this invention will in no way interfere with the mounting of the piston on a mandrel for nishing the outer surface of the piston. Moreover, the piston can be conveniently, eiectively and accurately centered on a mandrel by reason of the concentric rib at the mouth or end of the piston skirt, while the close proximity of the eccentric rib, adjacent, contiguous or merging with and into the concentric rib as one, enhances the major elimination of chatter or vibration of the piston, rounded wearing of the rings and oil pumping.

What is claimed is:

l. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottom upwardly.

2. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottom upwardly, said eccentric rib having its widest part diametrically opposite said slot.

3. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottom upwardly, said concentric rib extending throughout inwardly of the eccentric ring.

4. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottom upwardly, said eccentric rib having its widest part diametrically opposite said slot, said concentric rib extending throughout inwardly of the eccentric ring.

5. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottom upwardly, said eccentric rib having its upper surface merging gradually into the inner surface of the skirt.

6. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottorn upwardly, said eccentric rib having its widest part diametrically opposite said slot, said eocentric rib having its upper surface merging gradually into the inner` surface of the skirt.

7. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth,` a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottom upwardly, said concentric rib extending throughout inwardly of the eccentric ring, said eccentric rib having its upper surface merging gradually into the inner surface of the skirt. l

8. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib, said concentric rib and skirt having a slot extending from the bottom upwardly, said eccentric rib having its widest part diametrically opposite said slot, said concentric rib extending throughout inwardly of the eccentric ring, said eccentric rib having its upper surface merging gradually into the inner surface of the skirt.

9. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and

an eccentric rib within said mouth end merging with the concentric rib as one, said concenf tric rib and skirt having a slot extending from the bottom upwardly at the narrowest point of the eccentric rib.

10. In a hollow piston having an open mouth at one end and having a skirt extending upwardly from the mouth, a rib extending concentrically of the axis at the mouth thereof, and an eccentric rib within said mouth and merging with the concentric rib as a single integral unit, said concentric rib and skirt having a slot extending from the bottom upwardly, said eccentric rib having its Widest part diametrically opposite said slot, the thickest part of the eccentric rib being of less radial extent than the 15 radial extent of the concentric rib so that no part of the eccentric rib extends inwardly of the concentric rib.

NEWTON J. BUREN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS d Name Date 1() Number 1,478,361 Metzger Dec. 18, 1923 1,885,681 Buren Nov. 1, 1932 FOREIGN PATENTS Number Country Date 376,710 Great Britain Jan. 8, 1931 

